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Author Topic: Filament thins out then bukobot stops  (Read 457 times)

maq3396

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Filament thins out then bukobot stops
« on: October 24, 2013, 06:40:03 PM »
Hi,

Printing PLA at 220, bed 70
Base layers print extremely well.
However, at variable time in the print (never far into it) the filament starts to thin out then in rapid succession the bukobot stops with the extruder sitting on the print.
Have reloaded software, flashed firmware, changed usb cable, turned off all electrical sources around it. Tried different files as well.
When the next print is attempted the pva flows freely and there is no temperature drop to explain a jam.Drive gear looks ok
Any thoughts?

Thanks
Mac

whosawhatsis

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Re: Filament thins out then bukobot stops
« Reply #1 on: October 24, 2013, 09:46:20 PM »
That's a strange one. Does the machine respond at all if you click "Kill job" after this failure? Do you get any output in the console when this happens?

maq3396

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Re: Filament thins out then bukobot stops
« Reply #2 on: October 25, 2013, 03:56:49 AM »
I have a few more observations now...

It gives an Error 1 and a low temp warning

Going to swap extruders- a thermistor or connection issue?


whosawhatsis

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Re: Filament thins out then bukobot stops
« Reply #3 on: October 25, 2013, 07:29:27 PM »
Sounds like loose wiring. Keep the temperature monitor view open while you print and see if it shows the temperature slowly dropping in a curve or spiking down to zero, this will tell you whether it's the heater or the thermistor that is malfunctioning.

maq3396

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Re: Filament thins out then bukobot stops
« Reply #4 on: October 28, 2013, 10:26:30 PM »
Thanks,

Swapped over the extruders and it seems to not have that issue any more.

Will troubleshoot that unit when the dust settles here.

Have another one however....

On at least 50 percent of the last 6 prints the print "moves over" in the Y direction like the bed has slipped. I continues to print from this shifted point on upwards!

The bearings are firmly secured and the glass does not appear to have moved.

As it auto resets the Y axis I'm not sure how to tell if it is the cable/pulley that is slipping or not.

The pully is securely attached to the flattened portion of the motor shaft and the cable is quite taught (like a guitar string)

Guess the next move is to mark the cable and pulley

Any thoughts?

Thanks
Mac


Herb

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Re: Filament thins out then bukobot stops
« Reply #5 on: October 29, 2013, 12:25:19 AM »
I've seen this on one or two occasions, but I haven't been able to reproduce it. My only theory is that the extruder has deposited an excess of plastic in some spot, and then when the platform moves, the nozzle hits this lump of plastic and stops the platform from moving as far as it should.
Bukobot Duo v2

whosawhatsis

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Re: Filament thins out then bukobot stops
« Reply #6 on: October 30, 2013, 09:16:12 PM »
What you're seeing is the result of the stepper motor skipping steps. It can be caused by the nozzle hitting excess plastic, by the acceleration/jerk settings being too high for the motor's torque (you may need to turn the current up a bit), by excess resistance on the linear bearings, etc. The acceleration/jerk settings are set so that a properly-tuned machine should never be able to skip in this manner. Make sure your bearings are properly lubricated and sliding smoothly, then consider increasing the current to that motor.

maq3396

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Re: Filament thins out then bukobot stops
« Reply #7 on: November 11, 2013, 08:35:18 PM »
Thanks once again!

Greased the x and y rods and the issue disappeared.

Cheers
Mac

 

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